1. Field of the Invention
The present invention relates to a polymerase chain reaction (PCR) module and a multiple PCR system having the PCR module, and more particularly, to a PCR module capable of preventing contamination of a detecting unit and a heater unit when installing or removing a PCR chip, and a multiple PCR system including the PCR module.
2. Description of the Related Art
Polymerase chain reaction (PCR), which is a technology to amplify DNA copies of specific DNA or RNA fragments in a reaction container, is an epoch-making development in life science technology. In the PCR technology at the beginning, PCR products are separated on a gel and the approximate amount of the PCR products is estimated. Recently, however, co-amplification of different samples at different temperatures has been carried out and precisely monitored in real-time.
FIG. 1 is a schematic block diagram of a multiple PCR system 1 disclosed in Korean Patent Application No. 10-2004-0102738 filed by the applicant of the present invention on Dec. 8, 2004. In the multiple PCR system 1, co-amplification of different samples at different temperatures is performed in addition to monitoring the PCR reaction process in real-time, as described above. Referring to FIG. 1, the multiple PCR system 1 includes a plurality of PCR modules 40 and a host computer 50, which controls the PCR modules 40 and collects data. Each of the PCR modules 40 performs a PCR reaction on a single sample at a specific temperature and monitors the process and transmits the monitoring results to the host computer 50 in real-time. Any number of PCR modules 40 can be detachably installed in the PCR system 1 and connected to the host computer 50.
50 in real-time. Any number of PCR modules 40 can be detachably installed in the PCR system 1 and connected to the host computer 50.
As illustrated in FIG. 1, each of the PCR modules 40 includes a detachable microchip-type PCR reaction container (hereinafter referred to as a PCR chip) 10, a detecting unit 30 that detects a PCR product signal based on the amount of a PCR product of a sample solution (hereinafter referred to as a PCR solution) contained in a PCR reaction chamber (hereinafter referred to as a PCR chamber) 11 of the PCR chip 10 in which a PCR reaction is to occur, and an operation control unit 41 that automatically controls the whole PCR process and transmits and receives data to and from the host computer 50. The detachable PCR chip 10 can be used once or repeatedly. The PCR chamber 11 in which the PCR solution is accommodated and where the PCR reaction occurs is formed in the PCR chip 10. The PCR module 40 further includes a heater 20 contacting the bottom surface of the PCR chip 10 and transmitting heat so that the temperature of the PCR chip 10 is maintained at an appropriate temperature. A separate power supply device 51 applies a constant voltage to the heater 20. In addition, the PCR module 40 may further include a cooling device 43 besides the heater 20 so that the temperature of the PCR solution inside the PCR chip 10 quickly reaches a target temperature.
The detecting unit 30 in the PCR module 40 includes a light source 31 or an AC power supply unit 33, and detects a PCR product signal based on the amount of a PCR product. The PCR product signal may be a fluorescent signal emitted from the PCR chamber 11 disposed inside the PCR chip 10. In this case, the detecting unit 30 includes the light source 31 which emits light onto the PCR solution. After the light is emitted from the light source 31 onto the PCR solution, a fluorescent light emitted from the PCR solution is detected by a detector (not shown). The PCR product signal can also be an electrical signal, in which case the detecting unit 30 includes a sensor (not shown) for detecting the electrical signal. The sensor installed inside the PCR chip 10 senses a PCR product signal generated when an AC current is supplied to the PCR solution and transmits the sensed PCR product signal to the host computer 50. To do this, the detecting unit 30 includes the AC power supply unit 33 instead of the light source 31.
The operation control unit 41, which transmits and receives data to and from the host computer 50 by automatically controlling the entire PCR process, includes a central processing unit (CPU) 42 composed of a microprocessor, an auxiliary memory device 44, and a random access memory (RAM) 45, and controls the PCR process according to a set program. The operation control unit 41 independently controls the detecting unit 30, the PCR chip 10, the heater 20, the cooling device 43, and the power supply device 51 via a data communication unit (not shown) in real-time. Also, the operation control unit 41 performs a predetermined operation according to the set program or predetermined parameter values set by a user after performing appropriate operations based on information obtained from the sensor adhered to the detecting unit 30, the PCR chip 10, the heater 20, and the cooling device 43 or the data communication unit. For example, according to the PCR process, the temperature of the PCR chamber 11 is appropriately controlled, or operation of the cooling device 43, the detecting intervals of the detecting unit 30, etc. can be controlled. In addition, the operation control unit 41 may further include a separate input and output device 46 so that the PCR module 40 can be independently driven.
FIG. 2 is a schematic perspective view of the multiple PCR system 1 illustrated in FIG. 1. As illustrated in FIG. 2, the multiple PCR system 1 has a space in which a plurality of modules 40 can be accommodated. A plurality of slots (not shown) are formed in the space in which the PCR modules 40 can be installed, and thus the PCR modules 40 are easily detachable. Also, a display unit 60 which displays data received from the PCR modules 40 and an input unit 70 in which the user inputs required signals are installed in the multiple PCR system 1.
FIG. 3 is a perspective view of one of the PCR modules 40. As illustrated in FIG. 3, the PCR module 40 includes a main body 48 and a cover 47 installed on the main body 48 capable of performing a hinge motion. A pin 49 in which a plurality of electrodes are formed is formed on the bottom surface of the main body 48. The PCR module 40 can be installed in the slot in the PCR system 1 via the pin 49. When the PCR module 40 uses, for example, a fluorescent signal as the PCR product signal, a detecting unit 30 composed of an optical system including a light source having lenses is installed in the cover 47. Also, a space for accommodating the PCR chip 10 is formed in a portion of the main body 48 corresponding to the detecting unit 30, and the heater 20 is installed below the space. In such a structure, if the cover 47 closes by rotating the cover 47 after the PCR chip is placed in the space above the heater 20, the detecting unit 30 of the cover 47 faces the PCR chamber 11 of the PCR chip 10, and thus, the fluorescent signal emitted from the PCR solution within the PCR chamber 11 can be detected. As illustrated in FIG. 4, the PCR chamber 11 in which the PCR solution is accommodated is formed in the PCR chip 10, the PCR solution flowing in via an inlet 12 and flowing out via an outlet 13. Thus, the detecting unit 30 can detect the fluorescent signal emitted from the PCR solution during the PCR reaction.
However, in the PCR module 40 having the above-described structure, the optical system in the detecting unit 30 is exposed to the outside when mounting the PCR chip 10 in the PCR module 40, and thus the detecting unit 30 is susceptible to contamination. As a result, the accuracy of measured values is reduced. The heater 20 also gets contaminated when installing the PCR chip 10, thereby making it difficult to appropriately adjust the temperature of the PCR solution inside the PCR chip 10. In addition, because the user places the PCR chip 10 on top of the heater 20, the heater 20 and the PCR chip 10 can get damaged due to carelessness and it is difficult to adhere the heater 20 and the PCR chip 10 with the optimum pressure. Furthermore, it is inconvenient for the user to use since the cover 47 of the PCR module 40 needs to be opened and closed whenever installing or removing the PCR chip 10.